The present invention relates to a non aqueous liquid composition with an ionic character resulting from the contacting of at least one alkylaluminum dihalide with at least one quaternary ammonium halide or/and at least one quaternary phosphonium halide, said composition being liquid below about 80.degree. C. and preferably at temperatures lower than or equal to about 40.degree. C..
The object of the present invention is also the use of said liquid composition as a solvent (notably for catalysts).
Only few non aqueous ionic compositions which are liquid below the room temperature and one constituent of which is soluble in aliphatic hydrocarbons are known. Those which have been studied most are formed by the mixing of aluminum trichloride or tribromide with N-alkylpyridinium and N,N'-dialkyl imidazolium chlorides or bromides. These liquid ionic compositions are called "molten salts" (C. H.. HUSSEY, Advances in Molten Salts Chemistry, Vol.5, p.185, Elsevier, New-York, 1983).
The use of these molten salts as solvents and cocatalysts for the dimerization or codimerization reaction of olefins catalyzed by nickel cationic complexes comprising a nickel-carbon or a nickel-hydrogen bond has also been described in French patent 2,611,700.
It has now been discovered that the contacting (in any order) of at least one alkylaluminum dihalide (for example a dichloride or a dibromide) with at least one quaternary ammonium halide (for example a chloride or a bromide) or/and at least one quaternary phosphonium halide (for example a chloride or a bromide) and also possibly with at least one aluminum trihalide (for example an aluminum trichloride or tribromide) leads to a non aqueous liquid composition with an ionic character, said composition being liquid below about 80.degree. C. (for example between about -70.degree. C. and about +80.degree. C.), preferably at temperatures lower than or equal to about 40.degree. C. (for example between about -70.degree. C. and about +40.degree. C.) and, more preferably, at temperatures lower than or equal to about -20.degree. C. (for example between about -70.degree. C. and about -20.degree. C.). Besides, said liquid composition is stable with respect to time.